When I lately had the honour of reading a paper before the Society, on the Mustard Tree of Scripture, I ventured to make some observations on what I considered to be the requisites for, and the best mode of pursuing, as well as upon what we should admit as proofs in, such enquiries. I proceed now to treat of another Biblical plant, which is not less interesting than the Mustard Tree to determine. This is the Hyssop, frequently mentioned in the Old, and twice independently in the New Testament, and which, if we are to judge by the numerous attempts which have been made to ascertain the particular plant that is meant, is not less difficult to determine, than any one of the several unascertained plants of the Bible.